Florida Agricultural Experiment Station


Mature oak leaves, grass, straw and such materials high in
cellulose are difficult to wet and naturally require more water
than green, succulent plant materials, such as crotalaria, beggar-
weed or water hyacinth. The rainfall in Florida normally can
be expected to supply a large part of the water required. How-
ever, with mature plant materials it will be necessary to add
some water for initiating the decomposition process and for
temperature control.
 Air.-Decomposition in the compost is primarily aerobic and
if air is excluded it will be slow and incomplete. With ordinary
mature plant materials, such as dry grass, straw or leaves, the
small compost heap will be loose and too well aerated. In such
instances the compost should be thoroughly wet and well com-
pacted. If the compost heap is only 8 to 10 feet wide and 3 to 5
feet high there will usually be sufficient air for rapid decom-
position. If the material is finely divided or a pit is used where
the bottom may become waterlogged, a 4-inch tile laid from
the corners to the center of the heap and an upright through
the center will provide adequate aeration.
 Nitrogen.-The microorganisms bringing about the decom-
position of the compost require nitrogen. The amount of nitro-
gen required per unit of material decomposed varies somewhat
with the different organisms active in the process. The molds,
a group of organisms active in the decomposition of compost,
require about 1 part of nitrogen for every 30 parts of carbon.
The ratio of nitrogen to carbon in the plant materials determines
the rate of decomposition and the amount of nitrogen that


Fig. 2.-Water hyacinth compost No. 1 after 2 weeks.